Inputting TraditionalForm Expressions

In Version 2.2, the default input was and the default output was . In Version 3.0, the default input and output are both set to .
provides good readable two-dimensional typeset input and output and is mathematically
unambiguous because it uses Mathematica syntax.

Nevertheless, many users would like their input and output to be presented more
attractively and to correspond to mathematical syntax as far as this is consistently
possible. To this end, Version 3.0 provides . can
be selected as the default input and output format via Default Input FormatType and
Default Output FormatType under the Cell menu.

Since is,
with some slight reservations, the most attractive input and output format, I have decided
to use it in these columns. Also, where required, I will use the package (the latest version of which is
available from http://www.wolfram.com/~jasonh/Notation.html).

It may not always be obvious how to input typeset expressions in . Probably the easiest way is to type the
expression in a cell
using normal syntax, for example,

and then use Convert To&#x22B3;TraditionalForm on the cell:

Note that this expression is not just a with a subscript and
superscript .
Unformatting the expression (using Show Expression under the Format menu) reveals in a at its heart:

Here are four examples of the power and convenience of input notation: directional limits,